As an alternative to the previously-reviewed shelving system, I recommend Unistrut, a system of slotted metal channel, framing and tubing that can be connected and interconnected with various nut and bolt fittings to create storage racks, shelving, work tables, support for overhead lighting and a lot more. The parts are industrial quality (steel and/or pre-galvanized steel), but priced to be used everywhere. If you want to see it in use, go into any garage, gym or building where the structure is exposed. You will usually see Unistrut brackets used to hold up the water pipes for the fire sprinklers. The real wonder of the stuff is that you are not limited to using it on the wall; they have a large variety of fittings available specifically for hanging. It’s often used to anchor mezzanines and catwalks in warehouses.
The variety of fittings makes Unistrut very versatile. My dad uses it to make ski and ladder racks in the garage in the 8 inches of space above the garage door and the ceiling. He also used the tracking system to make a sliding door. I once welded a bunch of shelf brackets for him out of 2 x 2 x 1/4 inch angle iron. You can create shelving with the light gauge, 1 1/4-inch width channel or with the heavier gauge, 1 5/8-inch width with 24 inch brackets, which is good for 1200 pounds. The fail weight is two or three times the rated weight. We have a pile of the stuff in the back of our shop next to the scrap wood. If the shelf needs more capacity, we usually just double them up. What’s also wonderful is that if you don’t want to purchase pierced channel and/or additional brackets, you can take any standard bracket, drill a bolt hole, and create adjustable shelving. You can buy Unistrut fittings online. Channel, the part which is expensive to ship, can be found next to electrical conduit at Home Depot.